Tumor-directed Radiation Therapy for Patients With the Highest Risk Category of Localized Prostate Cancer

Inclusion Criteria: * Life expectancy \>5 years * Age ≥18 years * World Health Organization (WHO) performance status 0-2 * Histological evidence of prostate cancer * Classified as very high-risk according to national guidelines (2-3 of following high risk criteria: T3 / Gleason grade 8 /Prostate-specific antigen (PSA) 20-49 μg/L or and/or Gleason score 9-10 and/or PSA ≥40 μg/L * At least one Prostate Imaging-Reporting and Data System (PI-RADS) 4-5 lesion on diagnostic Magnetic resonance imaging (MRI) * Patients must be able to comply with the protocol * Signed informed consent * Adequate laboratory findings: haemoglobin (Hb) \>90 g/L, absolute neutrophil count \>1.0x10\^9/l, platelets \>75x10\^9/l, bilirubin \<2.0 x upper limit of normal (ULN), alanine aminotransferase (ALAT) \<5x ULN and creatinine \<2.0x ULN) Exclusion Criteria: * Regional or distant metastasis * Any contraindications for MRI * PSA \>150 ng/ml * Previous pelvic radiotherapy * Prior prostate surgery including transurethral resection of the prostate (TURP) * Endocrine treatment (past or present) * Other malignancies than prostate cancer and basalioma in the past five years * Serious disease state that makes study inclusion and treatment unsuitable * Severe lower urinary tract symptoms (International Prostate Symptom Score (IPSS) ≥20)